<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <div id="app">
    <h2>当前计数:{{counter}}</h2>
    <!-- <button v-on:click="add">+</button>
    <button v-on:click="sub">-</button> -->

    <!-- 语法糖的写法 -->
    <button @click="add">+</button>
    <button @click="sub">-</button>
  </div>
  <script src="../js/vue.js"></script>
  <script>
    const app = new Vue({
      el: '#app',
      data: {
        counter: 0,
      },
      methods: {
        add() {
          console.log('add被执行')
          this.counter++
        },
        sub() {
          console.log('sub被执行')
          this.counter--
        }
      },
    })
  </script>
</body>
</html>